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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_GFX_WIN_RENDERING_WINDOW_MANAGER_H_
#define UI_GFX_WIN_RENDERING_WINDOW_MANAGER_H_
#include <windows.h>
#include "base/containers/flat_map.h"
#include "base/memory/scoped_refptr.h"
#include "base/no_destructor.h"
#include "ui/gfx/gfx_export.h"
namespace base {
class SingleThreadTaskRunner;
}
namespace gfx {
// This keeps track of whether a given HWND has a child window which the GPU
// process renders into. This should only be used from the UI thread unless
// otherwise noted.
class GFX_EXPORT RenderingWindowManager {
public:
// The first call to GetInstance() should happen on the UI thread.
static RenderingWindowManager* GetInstance();
RenderingWindowManager(const RenderingWindowManager&) = delete;
RenderingWindowManager& operator=(const RenderingWindowManager&) = delete;
void RegisterParent(HWND parent);
// Registers |child| as child window for |parent|. Allows the GPU process to
// draw into the |child| HWND instead of |parent|. This will fail and do
// nothing if:
// 1. |parent| isn't registered.
// 2. |child| doesn't belong to |expected_child_process_id|.
//
// Can be called from any thread, as long GetInstance() has already been
// called on the UI thread at least once.
void RegisterChild(HWND parent, HWND child, DWORD expected_child_process_id);
void UnregisterParent(HWND parent);
bool HasValidChildWindow(HWND parent);
private:
friend class base::NoDestructor<RenderingWindowManager>;
RenderingWindowManager();
~RenderingWindowManager();
// UI thread task runner.
scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
// Map from registered parent HWND to child HWND.
base::flat_map<HWND, HWND> registered_hwnds_;
};
} // namespace gfx
#endif // UI_GFX_WIN_RENDERING_WINDOW_MANAGER_H_